Laboratory apparatus for treatment of cellulosic material continuously fed through acontainer



1966 o. J. RICHTER LABORATORY APPARATUS FOR TREATMENT OF CELLULOSIC MATERIAL CONTINUOUSLY FED THROUGH A CONTAINER Flled Sept 16, 1963 INVENTOR. g z Wm Aw/ w y- United States Patent 3 293 119 LABORATORY APPAhAfUs FOR TREATIVIENT 0F CELLULOSIC MATERIAL CONTINUOUSLY FED THRQUGH A CONTAINER Ole Johan Richter, Karlstad, Sweden, assignor to Aktiebolaget Karnyr, Karlstad, Sweden, a company of Sweden Filed Sept. 16, 1963, Ser. No. 309,245 Claims priority, application Sweden, Sept. 21, 1962, 10,149/62 5 Claims. (Cl. 162237) The invention relates to a laboratory apparatus comprising a cylindrical container intended for the performance of various treatments, preferably digestion cooking, of cellulosic material during its continuous passage through the container.

When making laboratory tests it is important to try to reproduce as closely as possible the conditions of the full-scale apparatuses so that the result of the tests becomes representative. In batch digestion of cellulose, wherein the chips are stationary and different phases of the digesting process involve the exchange of liquors, heating or cooling, gasing or gasing-oif etc., there are hardly any difliculties connected with the reproduction of the industrial process on a laboratory scale. On the other hand, during the development of continuous digesting processes, wherein a column of chips is fed continuously from one end of the digester to the other end and the chips pass through stationary zones, which perform different phases of the digesting process, along the length of the digester, it has been a disadvantage to be unable to perform corresponding digestion tests on a reduced scale. What above all has prevented the manufacture of a continuous miniature digester for laboratory purposes is the impossibility of reducing the dimensions of the charging and discharging devices to the required degree as long as the size of the chips is held normal or approximately normal, this being a condition for a fairly true reproduction in the laboratory of the conditions prevailing when cooking on an industrial scale. This disadvantage in being unable to reproduce industrial processes on the laboratory scale became particulanly acute after the introduction of two-stage digestion processes because it has not been possible in the laboratory to explore and demonstrate the possibilities and advantages of the continuous process in comparison to batch digestion. The same applies to other continuously performed treatments, such as, e.-g., bleaching.

The object of the present invention is to obviate said disadvantage and to create a laboratory apparatus of the kind mentioned, in which said difficulties in connection with the charging and discharging of the chips are eliminated. According to the invention, said apparatus is essentially characterized in that the container on opposite sides of a central treatment zone is provided with more or less inactive end parts of a considerably greater length than said central zone and in that a perforated or slitted tube for holding the treated material is completely enclosed within the container and the outer diameter of which approximately corresponds to the inner diameter of the end parts of the container, is displaceablle through the central zone in order to bring the material from one end part of the container to the other.

An embodiment of the apparatus according to the invention, reproducing a continuous digester will be more closely described herein below with reference tothe accompanying drawing, wherein FIG. 1 is a diagrammatic longitudinal sectional view of the apparatus and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1.

3,Z93-,1 l9 Patented Dec. 20, 1966 As shown in the drawing, the apparatus consists of a long and narrow container having a cylindrical wall, the central zone 11 of which is inserted between and by means of flange connections removably attached to end' part 13, 15 having a considerably greater length than said central zone 11. The central zone forms the digester proper, wherein various treatments should be performed, whereas the end part 13 replaces the charging devices and the end part 15 replaces the discharging devices in digesters of normal size. Preferably, the end parts may be 4 to 10 times as long as the central zone; e.g., the central zone may have a length of 1 m. and either end part a length of 5 m., whereas the diameter may be 0.2 m. Preferably the digester extends horizontally, but it can also be placed in a vertical or inclined position.

The central part 11 is equipped with means for performing the kind of digestion to be tested. The embodiment shown in FIG. 1 is primarily adapted for performing a sulphate cook with subsequent cooling of the pulp, and therefore two circulation systems are connected to the digester wall. The former which serves for heating purposes comprises an outlet 17 in the digester wall, a pump 19, a heat exchanger 21 with a steam supply conduit 23, and an inlet 25 located opposite to the outlet 17 so that a cross current of heated digesting liquid can be maintained through the chips column which is fed in the direction of the arrow 27 in a manner to be described below. The other circulation system which is provided for cooling is made similarly and comprises an outlet 29 in the digester wall, a pump 30, a cooler 31 with a cooling Water supply conduit 33, and a return inlet 35. With said cooling after the finished digestion there may be combined a washing of the pul part of the digesting liquor discharged through the outlet 29 being taken out of the circulation and replaced by water introduced into the pump 30.

The chips to be treated are contained in a perforated or slitted tube 37 closed by bottoms at the ends and the outer diameter of which approximately corresponds to the inner diameter of the digester so that the tube is guided in the digester with a slight clearance and is displaceablein the longitudinal direction. The length of the tube is approximately equal to the length of either end part of the digester, so that the tube can be brought from a starting position, in which it is completely enclose-d within the digester end part 13, through the central zone 11 to another extreme position lying completely within the digester end part 15. Attached to the end bottoms of the tube is a wire 39 which is drawn through an outer conduit 41 connected to opposite ends of the digester. Said conduit serves for equalization of the pressure and makes a flow of liquid from one end to the other possible which liquid else would oppose the motion of the tube 37 with the chips. In a casing fluid-tight attached to the conduit 41 is inserted a wire sheave 43 around which the wire 39 runs and the shaft of which is connected to a driving means and to a pointer, a counter or similar which due to its connection to the tube 37 by the wire 39 indicates the position of said tube in the digester.

The inlets and outlets of the central part 11 of the digester are positioned on bulges 45, 47 of the digester wall located diametrically opposite to each other. Therefore, the circulating liquid introduced through the inlet 25 spreads over a part of the length and circumference of the tube 37 before it passes transversely through the tube and the chips filling therein. Through the uncovered part of the circumference of the opposite side of the tube, the liquid flows out into the bulge 47 from where it is discharged through the outlet 17. The said bulges of the digester wall fonm compartments which are separated from each other on account of the close tolerances be- 3 tween the cylindrical digester wall and the tube 37 at other places, as shown in FIGURE 2.

When the digester should be taken into operation, the digester end-part 15 is disconnected and the tube 37 filled with chips is put into its starting position at the extreme right in the digester part 13. After the end part 15 has again been connected, the digester is filled with liquid which then by means of a pump and a control valve is put under the pressure which should be maintained during the digestion, e.g., to atmospheres gauge. Said pressure liquid preferably consists of the liquor used for the digesting test, so that the chips are impregnated therewith already in the digester end part 13 preliminary to the cooking. .The rest of the treatment takes place exclusively in the central zone 11, through which the tube 37 with the chips column is SlOWllY and continuously moved by the rotation of the wire sheave 43.

According as the digester chips are transferred to the digester part 15 the treatment practically ceases. When the whole length of the chips column has been treated, the digester is opened and the material in the tube 37 is emptied and examined as to its properties in order to evaluate the various working conditions chosen for the digesting tests.

The central zone 11 may be completed with further devices enalbling performance of still more complicated processes. Preferably the central zone is made exchangeable, and a set of central zones may be provided which are used alternately. The central zone may also be composed of a number of similar or dissimilar units which are varied according to requirements. The various compartments wherein the treating liquids are introduced and drawn oif may be mutually offset in the longitudinal direction of the digester, so that the liquid is drive-n in cocurrent or counter-current through the chips. The abovedescribed embodiment may also be modified in other respects without departing from the scope of the invention as set forth in the following claims.

I claim:

1. Laboratory apparatus comprising a cylindrical container intended for the performance of various treatments, preferably digestion of cellulosic material, during its continuous movement through the container, characterized in that the cylindrical container having a central zone and end parts on opposite sides of the central zone where the treatments should be performed, is provided with the end parts of a length considerably greater than the [length of said central zone, a f-oraminous tube is completely enclosed within the container and serves for holding the treated material and the outer diameter of which approximately corresponds to the inner diameter of the container, and means to displace the for-aminous tube through the central zone in order to carry the material from one end part of the container to the other end part thereof.

2. Apparatus according to claim 1, characterized in that the wall of the central zone of the container is formed with bulges located on opposite sides of the displaceable tube, to which bulges conduits are connected for circulating treatment liquids transversely through the tube.

3. Apparatus according to claim 1, characterized in that the tube is displaceable by means of a Wire connected to a driving means as well as to a device for indicating the position taken by the tube in the container.

4. Apparatus according to claim 1, characterized in the provision between the ends of the container, of an equalization conduit in which the wire is located.

5. Laboratory cellulose digester, comprising a cylindricall container having a central part and walls, liquid supply and withdrawal conduits connected to the wall of a central part of said container, a foraminous tube for holding a charge of cellulosic material to be tested, said tube, the outer diameter of which approximately corresponds to the inner diameter of the container, being enclosed in and axially displaceable in said container, and means for moving said tube past said central part of the container.

References Cited by the Examiner UNITED STATES PATENTS 278,284 5/ 1883 Slocum 23-472 1,679,525 8/ 1928 Hoye 23272 1,924,660 8/ 1933- Skolnik li6 2-l7 2,921,842 1/ 1960 List 23-2726 X DONALL H. SYLVESTER, Primary Examiner.

H. CAINE, Assistant Examiner. 

1. LABORATORY APPARATUS COMPRISING A CYLINDRICAL CONTAINER INTENDED FOR THE PERFORMANCE OF VARIOUS TREATMENTS, PREFERABLY DIGESTION OF CELLULOSIC MATERIAL, DURING ITS CONTINUOUS MOVEMENT THROUGH THE CONTAINER, CHARACTERIZED IN THAT THE CYLINDRICAL CONTAINER HAVING A CENTRAL ZONE AND END PARTS ON OPPOSITE SIDES OF THE CENTRAL ZONE WHERE THE TREATMENTS SHOULD BE PREFORMED, IS PROVIDED WITH THE END PARTS OF A LENGTH CONSIDERABLY GREATER THAN THE LENGTH OF SAID CENTRAL ZONE, A FORAMINOUS TUBE IS COMPLETELY ENCLOSED WITHIN THE CONTAINER AND SERVES FOR HOLDING THE TREATED MATERIAL AND THE OUTER DIAMETER OF WHICH APPROXIMATELY CORRESPONDS TO THE INNER DIAMETER OF THE CONTAINER, AND MEANS TO DISPLACE THE FORAMINOUS TUBE THRUOGH THE CENTRAL ZONE IN ORDER TO CARRY THE MATERIAL FROM ONE END PART OF THE CONTAINER TO THE OTHER END PART THEREOF. 